By considering the dynamics of dual mass flywheels, it is possible to estimate at least the torque with the help of primary- and secondary side rotation speeds during the operation of the drive train. Such estimated torque can be used for example as a controlling or regulating variable in order to control automated transmissions, for instance automatic shifting devices, automated manual transmission or twin-clutch transmission.
To determine the behavior of dual mass flywheels, the rotation speeds of primary and secondary speed transducers are evaluated and converted into engine- or load torque by means of the equations of motion. WO 2008/040282 A1 gives the generic state of the art in this regard, by which the real engine torque of a drive unit like an internal combustion engine is designed by means of state data of a dual mass flywheel. In this case, the engine torque values transmitted from the drive unit back to the dual mass flywheel are estimated and considered when determining the actually transmitted engine torque. The empirically determined characteristic data of the dual mass flywheel are mapped in a state-space model and after linearization by means of linear associations of energy accumulator spring rates, the induced engine torque is determined. Through linearization of the characteristic data, the solution of the respective equations of motion is simplified significantly, so that an estimated induced engine torque can be determined in real time during the operation of the drive train. Owing to the required linearization of the behavior of the dual mass flywheel when estimating the induced engine torque in real time, the non-linear behavior of the dual mass flywheels can only be simulated inadequately.
The task to propose a method for operating a drive train with dual mass flywheel is therefore encountered, which facilitates an improved processing of non-linear characteristic data of the dual mass flywheel in real time. In a further step, further costly data acquisition devices should be avoided and restriction be made to retain acquisition of primary and secondary rotation speeds.